As is well known to those skilled in the roofing art, the three leading generic types of commercial low-slope roof constructions are the torched on single-ply roof, the EPDM single-ply roof, and the built-up roof (BUR) construction. Generally speaking, the torched on single-ply roof construction comprises applying an insulation board cover to a steel deck or other suitable roof substrate and then securing an asphalt-coated polyester mat to the insulation boards by utilizing a hot torch flame to heat the underside of the membrane prior to adhering it to the insulation. The EPDM single-ply construction is very similar except that the thin EPDM membrane is glued to the insulation boards. Also, ballasting with heavy rock and spot attachment with fasteners are two other methods used to attach the EPDM membrane to the deck. Finally, the BUR roof construction normally provides for applying multiple reinforcement layers of asphalt saturated paper or fiberglass or spunbond polyester with hot-mopped asphalt applied between the layers in order to form a waterproof barrier over the roof substrate.
Unfortunately, all of the roof constructions described above suffer from inherent shortcomings which include lack of safety due to the requirement for open-flame torches, labor-intensive roof installation requirement, heavy and unwieldy roll roofing materials, splitting and blistering of the roof membrane, lap and seam failures, lack of puncture and tear resistance, failure in high winds, and non-uniform material qualities. In an effort to overcome some of these problems which have long plagued the commercial roofing industry, the panelized roofing system was developed. Quite a number of panelized roof systems are now known and they vary substantially in both their construction features and performance capabilities. Representative panelized roofing systems include the STRUCTODEK FS manufactured by Wood Fiber Industries of Chicago, Ill., the NORD BOARD system distributed by Nord Bitumi of Springfield, N.J., the INSULROOF distributed by American Roofing Corporation of Countryside, Ill., the panelized roofing system distributed by AB Mataki of Sweden, and panel systems disclosed in U.S. Pat. No. 4,680,909 to Stuart and U.S. Pat. No. 4,738,067 to Froseth. However, although potentially an improvement over conventional roofing systems, the panelized roofing systems have suffered from numerous shortcomings including relatively high cost, difficulty in cutting the panel boards, the requirement of open-torch flame application, easily damaged insulation boards, and physical irritation caused by fiberglass or rock wool insulation materials.
Applicant attempted to meet the long-felt need for a panelized roofing system with the novel roofing system described in applicant's recently issued U.S. Pat. No. 4,965,977. This roofing system has been found to be a vast improvement in the art, and applicant's new insulated panelized roofing system is a modification thereof to provide even greater flexibility in roof system constructions.